Fuel pump



May' `18,"1943 A F. Rf SUNDEMAN ETAL. `25319566 FUEL PUMP Filed May 2,1941 @m4/ym www@ ATTORNEYS Patented May 18, 1943 FUEL PUMP Frederick R.Sunderman,

New York, and

James McAuley, Bronx, N. Y., assignors to F. S. McLachlan Co. Inc., acorporation of New York Application May 2, 1941, serial No. 391,532

(o1. 12a-14o) 2 Claims.

This invention relates to fuel pumps for internal combustion engines andthe like and has for its object the provision of an improved fuel pumpof this character. The invention aims to provide a double-acting fuelpump having at least one pair of interconnected reciprocating pistonsdriven by a suitable crank means, each'piston being arranged to inject ameasured quantity of fuel oil from its cylinder into one enginecylinder. It is an Object of the invention to provide a fuel pump havingvalve means in cooperation with the pump pistons for accuratelymeasuring the amount of oil injected during each stroke of the pistonwhich is simple in construction and positive in operation.

The pistons of the fuel pump of the invention draw in a uniform quantityof oil on each intake stroke, and the amount is ordinarily more than isrequired for each injection. The amount of oil over that required fortheinjection is referred to herein as the excess oil. The pump pistons ofthe invention have passage means for returning the excess oil in thepump cylinders back into the oil storage system. The excess oil isreturned to the oil storage system without in any way interfering with,or altering the action of the pump pistons. The pump pistons reciprocateas a unitary structure and require no adjustments in varying the amountof oil injected during each stroke.

In a preferred and advantageous construction of the invention, eachpiston is provided with passage means arranged to connect with one of aplurality of ducts in the cylinder through which the excess oil may bereturned to the oil storage system. The invention comprises a separatevalve means for each pump cylinder having a by-pass for selectivelyconnecting any one of the said ducts to the oil storage system wherebythe excess of oil in the pump cylinder is returned to the oil storagesystem and the amount of oil for each injection is accurately measured.

Each pump cylinder and piston is constructed and arranged to permit acarefully measured quantity of oil which enters the pump cylinder fromthe oil storage system to be injected into the engine cylinder in acontinuous and strong stream. The pump piston travels under such speedand positive action that a strong stream is delivered from the injectionnozzle up to the very instant when the stream is out off.

The valve means preferably comprises an oscillatable member having aby-pass in the form of a small hole therethrough in continuous contactwith a conduit leading to the cil storage sysem and in adjustableContact with any selasted one of the ducts. The by-pass in the valve maybe placed in coincident engagement with any oneof the ducts which,during each piston stroke, connect with the passageway in the pumppiston. The oscillatable valve member may be provided with any suitablemeans for setting it to place the by-pass in coincident engagement withany selected duct, especially when it is desired to control the pumpmanually. The fuel pump may also be provided with any suitable governorresponsive to the speed of the engine for actuating the oscillatablevalve member of each pump simultaneously and automatically.

The pump pistons are arranged in their cylinders so that, at the end ofthe injection stroke, there is a small quantity of oil left in thecylinder.V In using a crank to reciprocate the pistons,

I' prefer to use a Scottish-yoke and to arrange the crank therewith sothat the piston, at the endof its injection stroke, returns relativelyvery rapidly and thereby cuts oi the oil injection very sharply andprevents oil dribble from the injection valve into the engine cylinder.

One of the important features of the invention is the arrangement of theoil inlet port in the cylinder in such a position with respect to thestroke of the piston that air in the cylinder is forced into the oilstorage system, thereby eliminating the necessity of bleeding out theair whenever parts of the pump nozzle or pipes have been repaired orreplaced.

These and other novel features of the invention will be betterunderstood after a consideration of the following discussion taken inconjunction with the accompanying drawing, in which:

Fig. 1 is a sectional side view of a fuel pump embodying the invention;

Fig. 2 is a sectional view along the line 2-2 of Fig. 1, and

Fig. 3 is a sectional view along the line 3 3 of Fig. 1.

The fuel pump illustrated in the drawing comprises a pump frame I havingtwo diametrically opposite pump cylinders 2 and 3 in which arereciprocably mounted the pump pistons 4 and 5 respectively. The pistonsconnect to the Scottish-yoke comprising the yoke member 6 having a slot,'I in which the crank 8 rotates. As shown in the drawing, the pistonsand yoke member are a unitary element. The pistons have passageways IIJand II extending from the face to the side and the cylinders areprovided with a plurality of spaced ducts I2, I3 and I4, and I5, I6 andI'I which connect the cylinders 2 and 3 with the cylindrical openings ofthe control valves 2|) and 2| respectively.

The control valves have oscillatable valve members 22 and 23 preferablyin the form of cylinders having the by-passes 24 and 25 respectively.The valves have oil conduits 26, 2l extending along the sides of thevalve members which also extend from an oi1 storage system (not shown)and also connect with the intake ports 28 and 29 of the cylinders.

'I he valve members are connected by eccentrically attached couplings 30and 3i to an adjustment member 32. The adjustment member has a manuallyoperated lever which slides in contact with an arcuate dial 34 providedwith a position-setting lock 35. By swinging the lever 32, the valvemembers 22 and 23 are each moved the same extent but in oppositedirections. By moving the lever to the proper positions, the by-pass maybe placed in communicating engagement with any 'one of the ducts.

The pump cylinders have discharge passages 40 and 4| leading to thevalves 42 and 43 which are normally held closed by the springs 44 and 45respectively. The valves control the flow of oil int-o the chambers 45and 41 and the passages 48 and 49 in the coupling members 50 and 5iwhich connect to the pipes (not shown) leading to the injection nozzlesof the engine. The areas of the valves subjected to oil pressure, andthe elasticity of the springs are selected so that a high oil pressureis required to lif-t the valve for each injection. An oil pressure ofaround 1750 pounds per square inch is ordinarily satisfactory. However,it is obvious that any suitable pressure may be used. The injected oilpasses up through the central passages 52 and 53 and is dischargedthrough radial ports 54 and 54a when the valves are raised.

As is best shown in Fig. 3, the shaft 55 which drives the crank 8 isconnected to the gear 56 which is connected to and driven by the engine.One end of the shaft carries the centrifugal governor 51 which comprisesthe weights 58 and 59, and sliding sleeve 60. 'I'he sliding sleeve 60has an annular groove 6l in which one end of the bell crank 62 isengaged. The other end of the bell crank engages a slot 63 (Fig. 1) inthe adjustment member 32. When the adjustment member 32 is locked inposition to the dial member 34, the governor is held in an inoperativeposition, and when the adjustment member is unlocked and free tooscillate, the adjustment member and valves 2li and 2| are under theccntrol of the governor.

In operating the pump of the invention, the adjustment member 32 may beset in any desired position and secured in that position by locking itto the arcuate member 3Q by the lock 35. The adjustment member is set insuch a position that the by-passes 24 and 25 are placed in coincidentengagement with one of the ducts, for example ducts I4 and I1. In this-position the pump is set to discharge the minimum quantity of fuelduring each injection. As one of the pistons, for example piston 5,moves to the left, the cylinder 3 fills with fuel oil. The pistonstrokes are such that, at the end of the intake strokes, there is aconsiderable space between lthe ends of the pistons and the ports 28 and29. This clearance permits any air which may be in the cylinder to beforced back into the oil storage system.

When the piston 5 starts to move towards the right from the positionshown in Fig. 1, a part of the oil and any air which maybe present isforced back through port 2,9 and conduit 21 into the oil storage system.After the piston passes beyond port 29, it then puts such pressure onthe oil that the valve 43 is raised against the action of the spring 45and the oil commences to ow to the injection nozzle of the engine. Whenthe passage II in the piston is coincident with the duct I1, the oilflows through the passage Il, duct I1, the by-pass 25 and into theconduit 21. This is the excess of oil over that required for theinjection and the remaining oil in the cylinder 3 is charged throughvalve 43 and into the injection nozzle.

When it is desired to operate the pump under the control of the speedgovernor 51, the lock 35 is disengaged leaving Ithe adjustment member 32to be actuated entirely by the governor. As the speed of the engineincreases and the centrifugal weights 58 and 59 are thrown outwardly,the sleeve 60 moves to the left, thus turning the bell crank 62 andmoving the valve members 22 and 23 to such positions that theirby-passes will con nect with one of the ducts returning a portion of theoil in the cylinders to the oil storage system. When the pump is underthe control of the governor, the regulation may be effected entirely byslightly oscillating the valve members to cause the by-ipass and theduct with which it is connectedto act as a throttling orifice. Thereturn of oil is, accordingly, varied by varying the size of the openingunder the action of the governor.

The pump unit illustrated in the drawings having one pair ofdouble-acting pistons is a unit suitable for supplying oil to two enginecylinders, the nozzle of each .cylinder being connected by suitabletubing to the couplings 50 and 5I. Any suitable number of such units maybe provided and each pair of pistons is preferably driven by the sameshaft.

We claim:

l. A fuel pump for internal combustion engines which comprises at leastone pair of opposed pistons each reciprocable in its own cylinder, acrank means for driving each piston, an oil passage in each piston, avalve for each piston having an oscillatable valve member, a by-pass inthe valve member, a conduit connecting an oil storage system, the valveand the pump cylinder, a plurality of ducts connecting each cylinderwith each valve, and means for adjusting the position of the valvemember to connect the by-pass with any one of the ducts and with theconduit, whereby the excess of oil over that required for each injectionis returned from the cylinder through the passage, duct and the by-passback to the conduit.

2. A fuel pump for internal combustion engines which comprises at leastone pair of opposed pisn tons each reciprocable in its own cylinder, acrank means for driving each piston, an oil passage in each piston. avalve for each piston having an oscillatable valve member, a by-pass inthe valve member; a conduit connecting an oil storage system, the valveand the pump cylinder; a plurality of ducts connecting each cylinderwith each valve at spaced intervals in the longitudinal direction of thecylinder, said ducts being arranged to effect selective and coincidentengagement with the by-ipass by adjustment of the valve member to varythe quantity of oil in each injection, means responsive to the speed ofthe engine operatively connected to the valve member whereby the valvemember is adjusted in accordance with the speed of the engine tothrottle the passageway between the duct and the by-pass and therebyvarying the supply of fuel to control the speed of the engine.

FREDERICK R. SUNDERMAN. JAMES MCAULEY.

